How do you stay patient with bureaucracy on a bad day?

Something I've been struggling with lately, not a practical question exactly. Most weeks I'm fine with the paperwork here. It's slow, it's different, it's fine. But some days I get a letter asking for a document I've already sent three times, or I wait an hour and get sent to another office, and I feel a kind of anger that I'm honestly not proud of.

I know the person behind the desk isn't the problem, and I know getting angry makes things slower, not faster. But on a bad day it's hard to stay calm.

How do you stay patient with bureaucracy on the bad days? Any small habits, mental tricks, or rules you set yourself? I'd especially like to hear from people who've been doing this for years.